Apparatus for testing plate seams



Feb. 15, 1938. H. L. NEWBY v EJUfiJWfi APPARATUS FOR TESTING PLATE SEAMSFiled June 30, 1936 Patented Feb. 15, 1938 Y UNITED STATES PATENT 0mm";

Howard L. Newby, Los Angeles, Calif. Application June so, 1936, SerialNo. ss,1s1

3 Claims. (Cl. 73-51) I This invention relates to an apparatus fortesting plate seams.

Ari object of the invention is to provide asimpleand inexpensivebuthighly satisfactory apparatus for testing various types of plate seamssuch as are present in steelor other tanks and like containers orreservoirs. Heretofore, where large tanks are made up of plates welded,bolted, riveted, or otherwise secured together, difliculty has beenexperienced in being able to locate leaks in'the seams. For example, inwelding the seams 'of plates of a large gasoline storage tank, weldershave been required to proceed very slowly in their welding so that thewelds will be free of gas pockets and blowholes which might permit oismall leaks.- .Even when the welding is done very slow- ,ly it isdifficultto ascertain whether or not leaks are present; This isparticularly true where the tank contains a highly volatile liquid, suchas gasoline, and is resting on the ground or is partially or whollyembedded in the ground. The leaking liquid, being highly volatile,evaporates so quickly as to conceal thefact that leakage is takingplace. In other tanks it is customary in many instances to build thebottom of the tank in an elevated position and endeavor to test itsseems for leakage by other means, after which the bottom is lowered intoits final position. The lowering frequently creates stresses and strainsthat produce leaks after the test.

An object of the present invention is to provide a new apparatus fortesting plate seams, whether produced by welding, riveting, bolting, orotherwise, which will easily and quickly enable the .testerto ascertainthe presence of leaks even though such leaks may be so small as to beimpervious to liquid but not to gases. I

By the improved apparatus, in the case of welded seams the welder mayproceed with his welding at a rapid rate and rely upon the tester toinform him of the presence of any gas pockets or blowholes which causeleaks. Furthermore, by use of the improved apparatus tanks may be builtin place and either internally or externally tested for leaks with theresult that very minute leaks can be ascertained and corrected and thetanks may be built in their final position and then tested, obviatingthe creation of leaks during lowering of tank bottoms into position.

Another object of the invention is to provide a means for testing tanksand like structures for leaks which will be highly inexpensive ascompared with present apparatus for testing.

With the foregoing and other objects in view, which will be mademanifest in the following deand specifically pointed out in the appendedclaims, reference is had to the accompanying drawing for an illustrativeembodiment of the invention, wherein: I

Fig. 1 is atop plan view of the major portion 5 of the apparatus usedfor testing plateseams embodied in the present invention.

Fig. 2 is a vertical section taken substantially upon the line 2-,-2 ofFig. 1.

Fig. 3 is a vertical section taken substantially upon the line 3- 3 ofFig. 2.

Figs. 4 and 5 are views illustrating modified forms of the apparatusthat may be employed in carrying out the method embodying the inventionherein disclosed. 15

Referring to the accompanying drawing, wherein similar referencecharacters designate similar parts throughout, two plates l0 and II areillustrated as having their edges lapped and welded by means of a weldl2 forminga seam between the two plates which it is proposed to test forleakage. While the plates are shown as having their edges lapped it willbe understood that the invention may be employed with other forms ofseams such as, for example, butt welds or butt joints. The apparatusconsists of a suitable container having walls l3 and a glass top H, theglass being readily transparent so that theinterior of the container orthe chamber 15 formed thereby may be readily viewed therethrough. Thebottom of the container is formed with a highly flexible or deformablegasket I6. I find that a material greatly suitable for this gasketconsists of sponge rubber to the sides of .which are applied liquidrubber latex serving to seal the pores of the sponge rubber. The spongerubber gasket, being highly deformable, is capable of accommodatingitself to the inequalities of the top surfaces of plates I 0 and II soas to hermetically seal the chamber I5 when the container is applied toa portion of the length of the same. The coating of latex merely sealsthe pores in the sponge rubber so that air will not seep there-'through. Any equivalent form of highly deformable material may besubstituted ior sponge rubber in providing the gasket.

In one wall of the container there is formed an outlet indicated at Hwhich may be connected by means of a hose ID to a vacuum pump not taileddescription,

shown. Associated with the container there is also preferably provided avacuum gauge l9.

In order to test the seam H for leakage the procedure is as follows:

A soap solution is formed consisting merely of soap a d water which isspread or painted along in the case of and over seam l2. The containeris then posi tioned over the seam and the vacuum pump started so as tocreate one or two pounds of vacuum within chamber IS. The presence ofthe vacuum in the chamber is determined from the vacuum gauge IS. Thetester then looks through glass l4 into the chamber to ascertain whetheror not any soap bubbles appear along the seam. It will be appreciatedthat the atmospheric pressure on the under side of seam I2 being greaterthan the partial vacuum formed in chamber I! air will tend to flowthrough any leaks in the seam and will create bubbles in the coating ofsoap solution. If such bubbles do occur the tester marks theirapproximate locationand the welder,- welded seam, corrects his work tostop the leak or leaks. If no soap bubbles appear the tester proceeds toshift the container along the seam, following the same procedure at eachlength of scam covered by the container. While other solutions may beemployed as a detecting medium in place of the soap solution, soapsolution is highly satisfactory in that it is relatively cheap andminute leaks become readily apparent 'due to the formation of the soapbubbles. v

In the case of bolted and riveted seams the .procedure is the same withthe exception that in making correction the bolts may be tightened up.rivets tightened or replaced, or the same may be caulked.

The degree of vacuum formed in the chamber does not have to be high. Adifferential in pressure betweenthe atmospheric pressure and the chamberpressure needonly be a few pounds in all ordinary testing. By means ofthe present apparatus very minute leaks can be detected, some of whichare so small that liquids will not ordinarily pass therethrough but onlygases; which is important in the case of gas tanks and tanks containinghighly volatile liquids. The pressure required to be applied to thecontainer by the tester in order to assure a seal being formed by thegasket l6 does not have to be excessive and as soonas the vacuum startsto form within chamber IS the atmospheric pressure bearing on thecontainer is effective to press the container tightly against theplates.

In Figs. 4 and I have illustrated slightly modified forms ofconstruction for testing seams. In Fig. 4, which is designed to testinside corner seams, the container is formed merely by a glass plate 20enclosed within a suitable frame 2|, to which the highly deformablegasket 22 is applied. In the end walls, one of which is shown at 23,there may be the outlet formed for connection to the hose leading to thevacuum pump. The vacuum gauge, not shown, may be installed anywhere tocommunicate with the interior of the chamber formed by this form ofconstruction. The operation and method of is the same as that previouslydescribed. The construction; however, is of such a design as to lenditself to the testing of seams such as those indicated at 24 and 25 onthe inside 'of corners.

In the construction shown in Fig. 5 the glass plate is indicated" at 26mounted within walls 21 which are provided with gaskets. Thisconstruction is of such shape as to be highly suitable for testing theseam 29 of an} external corner. The outlet from the chamber 30 and thevacuum gauge are not shown but are suitably mounted on one ofthe wallsdefining the chamber.

From the above described constructions it will be appreciated that animproved apparatus for testing plate seams is" provided which enablesseams to be easily, quickly, and accurately tested for leaks. It ispossible to test seams of tanks erected in their final position and totest old or previously constructedtanks for leaks. 'In this way thespeed of construction and manufacture of large tanks and reservoirs maybe materially increased ,and at the same time the manufacturer orbuilder may be assured that the completed tank is leakproo'f. V

The improved apparatus for testing plate seams is very inexpensive bothfrom the labor and material standpoi'nts as compared with presentapparatus' for testing. Itis not necessary to fill the tank to determineleaks or to impose internal pressures thereon as is required in someinstances. v

Various changes may be made in the details of construction and method ofoperation without departing from the scope of the invention as definedinthe appended claims.

I claim:

1. An apparatus for testing plate seams, comprising an open bottomedcontainer having a transparent wall and having a deformable gasket,means for creating a partial vacuum in the container, and means fordetermining that a partial vacuum exists within the container.

2. An apparatus for testing plate seams, com- .prising means providing atransparent wall,

means associated with the transparent wall for defining a chamberbeneath which a portion of a seam may be isolated, and means forcreating a partial vacuum within the chamber.

3. An apparatus for testing plate seams, comprising a transparent Wall,means associated with the transparent wall for defining a chamber, ahighly deformable gasket associated with said means, and means forcreating a partial vacuum within the chamber.

H. L. NEWBY.

